There is no Unicode byte order mark. Cannot switch to Unicode

Question

I am writing an XML validator with XSD.

Below is what I did, but when the validator reached the line while (list.Read()) it gives me the error

There is no Unicode byte order mark. Cannot switch to Unicode.

Can anybody help me fix it?

public class Validator
    {
        public void Validate(string xmlString)
        {
            Boolean bRet = true;
            string xmlPath = @"C:\x.xml";
            string xsdPath = @"C:\general.xsd";

            XmlReaderSettings Settings = new XmlReaderSettings();
            Settings.Schemas.Add("", xsdPath);
            Settings.ValidationType = ValidationType.Schema;
            Settings.ValidationEventHandler += 
               new ValidationEventHandler(SettingsValidationEventHandler);

            XmlReader list = XmlReader.Create(xmlPath, Settings);
            //StringBuilder output = new StringBuilder();
            while (list.Read()) 
            {
            }
            //File.WriteAllText(@"D:\Output.xml", output.ToString());
        }
        static void SettingsValidationEventHandler(object sender,
                                                   ValidationEventArgs e)
        {
            if (e.Severity == XmlSeverityType.Warning)
            {
                MessageBox.Show( "WARNING: ");
                MessageBox.Show(e.Message);
            }
            else if (e.Severity == XmlSeverityType.Error)
            {
                MessageBox.Show("ERROR: ");
                MessageBox.Show(e.Message);
            }
        }
    }

XML

<?xml version="1.0" encoding="utf-16"?>
<FlashList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:xsd="http://www.w3.org/2001/XMLSchema" vin="xxxxxxxxxxxxx">
  <flash ECUtype="xxx" />
</FlashList>

XSD

<?xml version="1.0" encoding="utf-16"?>
<xs:schema attributeFormDefault="unqualified" 
           elementFormDefault="qualified"
           xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="FlashList">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="flash" maxOccurs="unbounded" minOccurs="0">
          <xs:complexType>
            <xs:simpleContent>
              <xs:extension base="xs:string">
                <xs:attribute type="xs:string" name="ECUtype" use="optional"/>
              </xs:extension>
            </xs:simpleContent>
          </xs:complexType>
        </xs:element>
        <xs:element name="Error" maxOccurs="unbounded" minOccurs="0">
          <xs:complexType>
            <xs:simpleContent>
              <xs:extension base="xs:string">
                <xs:attribute type="xs:byte" name="code" use="optional" />
              </xs:extension>
            </xs:simpleContent>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
      <xs:attribute type="xs:string" name="vin"/>
    </xs:complexType>
  </xs:element>
</xs:schema>

Answer 1

The reality of your file's encoding appears to conflict with that specified by your XML declaration. If your file actually uses one-byte characters, declaring encoding="utf-16" won't change it to use two-byte characters, for example.

Try removing the conflicting encoding from the XML declaration. Replace

<?xml version="1.0" encoding="utf-16"?>

with

<?xml version="1.0"?>

You may also be able to load the file into a string as a work-around using LoadXML().

Answer 2

If you are not able to change the xml file encoding as

<?xml version="1.0"?>

Alternatively, you can read the xml content directly as raw xml instead of loading it with xml path.

XmlReader.Create(new StringReader(File.ReadAllText(fileName)));

If you use XmlDocument;

var xmlDoc = new XmlDocument();
xmlDoc.LoadXml(File.ReadAllText(filePath));

Answer 3

This error is thrown, when you declare encoding by UTF-16 in XML head, but physically don't save this file in such encoding.

You can check using simple Windows Notepad, clicking to Save As, and then in the bottom check encoding of xml file (probably it is still UTF-8, instead of UTF-16).

Screenshot of notepad encoding setting